Launching system for rocket driven devices



May l2, 1964 L. K, FREVEL LAUNCHING SYSTEM FOR ROCKET DRIVEN DEVICES 3 Sheets-Sheet 1 Filed May 16. 1961 r NNN@ Mx KQQKMYM Qu IN V EN TOR. ua/o K. Frer/e/ QOQUWW 06k S mmxw a. Mvg

May l2, 1954 1 K. FREVEL LAUNCHING SYSTEM EOE ROCKET DRIvEN DEVICES 5 Sheets-Sheet 2 Filed May 16, 1961 QQQQ IN VEN TOR. Luo/o /C r-eve/ May 12, 1964 K, FREVEL 3,132,562

LAUNCHING SYSTEM ECR ROCKET DRIVEN DEVICES Filed May 16, 1961 5 sheets-sheet 3 To acce/era/ar 6 ,zO/09e fab@ r/ Vesse/ lor/ng] Pis/0n ffy 5 IN VEN TOR. L udo A. Fre l/e/ 12 14 l i; i? BY LAUNCHING SYSTEM FR ROCKE DRIVEN DEVICES -Ludo' K. lhevel, Midland, Mich., assignor to The Dow Chemical Company, Midland, Mich., a corporation of Delaware Filed May 16, 1961, Ser. N0. 110,536 i v2 Claims. (Cl. 89-1.7) This invention relates to a launchingV mechanism and more particularly is'concerned with a system for launchfing rocket drivenvehiclesutilizing compressed low mo-` lecularweight gases as an accelerating medium for the rlaunching device. n l ,It'is a principal object of the present invention to pro- Ividelaj system for the launching of rockets and missiles which does-not depend on a Vchemically fueled rst stage rocket.

;-v Itisanother object of the present invention to provide 'a launching Vmeans for missiles and rockets which providesa uniform acceleration thereby preventing unde- 'V's'rable sudden stresses Vonjthe missile or rocket struci tureor housed instrumentsand equipment. l

. It is a further 'object ofthe present invention topro vide a means by which launching is'not affected or de- Ylayedbyweather conditions andwherein the missile or .'rocketvirtually cannot be subjected to sabotage during thelaunching operation.

Itis'an .additional object of the present invention to fpro'vide aA launching system wherein there isa storage Vreservoir of potential energy within a single unit for a large number of launchings.

., It.A is also an objectief the presentl invention to provide aA launching means .wherein there is no rusting, scouring o `lorbuild up of combustion product and chemical deposits on the walls of the launcher tube.

p Thesen and other objects and advantages .will becomef "apparent fromthe detailed description presented herevinafter'and by reference to the accompanyingdrawings.

i Inthe drawings- A' LFIGURE-'1 is a schematic View of one embodiment of the 4launching system.

FIGURE 2 is a schematic view of a secondjembodi- "mentor the launching system wherein the gas storage system has been modified from that shown in FIGURE l.

FIGURE 3 is a schematic cross section looking downward at the valve position of an accelerator tube Vand high-pressure gas storage tanks utilized in Vthe embodi- 'ment off-the launching system shown schematically in 'FIGURE 4 is a fragmentary schematic side View, partlyin section, of the accelerator tube and one of the gast storage tanks shown in FIGURES.

FIGURE 5 'is `a v1ew of a valve assembly used between ""agiven stage of the accelerator tube and a correspondying section of a storage tank taken along lines 5+5 of FIGURE 4.-

' FIGURE 6 is a schematicside View, partly in section,

'ofthe top section of the IURE'S. i' -FIGURE 7 depicits la control means for. activating 'y the'gate-valve assemblies.

accelerator tube shown in FIG- rocket orLrocket'driven missile is introduced into a partially evacuated' multistage vlaunching accelerator tube. -Compressedgas of pressure sucient to accelerate the 'rocket and heated Vtoa predetermined temperature is introduced -into the bottom of the iirst stage of the ac- *Yceleratorf tube where it exerts an upward driving force on the-rocket and movesit upward tothe next stage. yAs the rocket enters thisl stage more compressed gas',`;at a

f Vil'Ingaceordance with the present launching'system, a

.-somewhathigher temperatureand correspondingly higher Htube at a predetermined velocity.

; insa 3,132,562 Patented yMayr 12, ia64 kpressure is introduced intoi'kthe tubefrom the second section of the pressure chamberthereby` exerting a still Vgreater force on the rocket and promoting itsacceleration. This procedure is continued through a predetermined number of stagesusing the 'compressedgas in each stage at a higher temperature than for the preceding stage until the rocket or missile exits from the accelerator One preferred system for carrying out this method Aof launching is that shown inthe accompanying drawings l and '3-7. In this depicted embodiment of the launching mechanism, the accelerator tube is surrounded by ten gas lstoragev chambers Vextending substantially the length of the accelerator tube. These gas .stor- .age chambers are separately joined to the accelerator at each stage by individual conduit and gate valve means. Alternatively, as shown in FIGURE 2, the gas is stored in a suitable natural repository and fed through a manip fold system into the accelerator tube. 20.

The'acc'eleratontube, aslfabricated, .is of' precision smooth bore and is kept rigid and positioned by lthe'ten gas storage chambers surrounding it and ljoined to vthis tube. In underground installations, the free space between the gas storagegcontainers and the accelerator tube preferably' is vfilled with low-density, non-dusting, reproof granular rpellets Vof materials such asvermiculite, ydiatomaceous earth, mica, asbestos 4`and the like. In the event that hydrogen is employed as the driving. gas in such installations, a continuous nitrogen purge is maintained downward throughthe shaft containing the accelerator tubeand connectedgas storage chambers to exclude all air -from'around the hydrogen storage tubes.

Atthe bottom of the rst stage of thetaccelerator tube is a vacuum lock 'through which rockets Yand missiles are transportedfrom the missile stora'gearea to the evac- 'uated launching position.

The tube near its bottom also contains a vent system for removal and purging of excess gases after va launch- The ltop seetionv of theaccelerator tube, asshownin [FIGURE 6 comprises aremovable, e.g..explosive actuated dome 10, gate'valve assembly 1v1, connections'lZ to vacuum turbines (not shown) andalignment-screw assemblies 13.-v The gate valve V11,l when in closed position permits evacuation of themain part of the accelerator tube V'14 throug'ha multiplicity of connections 12e.g.

about 5l), in number, to Vacuum turbines (not shown).

Y The actualjoining of the tube connections to the turbines is accomplished through double-seal high-pressure llexible connections 15. *The `dome 10 is held tothe top ange V'16 Yof the tube by separately evacuating this portion of the system through connection 17. A exiblel O-ring 18 is inserted between the dome 10 ,and the flange 16 to insure Aa good seal.

Three precision-alignment screwl assemblies 13 'posi- --tioned at equal intervals around the top ange 16 KYofthe tube provide an aiming means.

Each of the-gas storage vessels is divided internally into sections (onebof which is shown in FIGURES 3 and 4) and each section is'equipped with a valving mech-` anism. Further, as is shownl in FIGURE 4, each of `these vessels is fitted withtungsten arcs in the upper por- -tion of each section `near theA conduit leading to the valvving mechanism c and accelerator tube. the gas pressure vessels are designed toQcorrespond to kthe stages Vof the accelerator tube. The sections of the The sections of pressurevessels alsoare fitted withjhighly polished stainless steel reilector linings which act as radiation` shields and prevent'` heating of the walls and body ofthe gas v storage vessels.

The valve systemutilized in the presenttembodim'ent Y compressed springs of the valve at the corresponding conduit. The expansion of the springs forces the gate open.

The ends of each of the shafts holdingr the springs, when the valve is in open position, each contact the end of a piston maintained in position by a second electromagnetic trip. As the rocket or missile passes to the next stage,

Vthe second trip is released and a set of pistons, which mate with the end of the shafts holding the springs of theV gate valve, strike the shafts thereby compressing the springs of the valve and closing `the conduit opening. The first electromagnetic trip is then engaged to secure the valve in the closed position. In the particular launching system shown in the drawings, at each stage there are 10 gate valves, lone for each of the gas storage chambers.

Advantageously, to insure a more perfect seal, the valve gate can be bonded to the valve housing by a low melting material, such as gallium metal for example. This sealing means itself is frozen or melted as desired by passing a suitable coolant or heated fluid throughy the passageV adjacent the seal.

All missile loading, chamber evacuating and valve trip- Vping and activation operations are carried out precisely and automatically. Conventional electronic, electromagnetic, radio wave and similar control systems can be employed in the automatic control systems. One particularly elfective means of automatically tripping the gate valve assemblies is shown in FIGURE 7. In this system a collimated yl-source, such as cobalt 60, and ay detector are mounted on the wall of the accelerator tube, as shown, at a predetermined position in a given stage. As the nose of the rocket intercepts the beam of radiation from the cobalt 60, this interruption'is sensed bythe detector. This detector, in turn, in conjunction with a second level detector (not-shown) andV suitable computing and Calibrating control systems shows the velocity and position of the `missi1e as a function of time. This information is then fed to conventional electronic, electromagnetic, radio or other similar relay mechanisms Vwhich in turn activate the electromagnetic releases thereby tripping the gate valves of the next successive stage of the launching tube and closing the gate valvesrof the stage through which the rocket has passed. Y

The materials of construction for the accelerator tube, gas pressure vessels, valves and the like will be selected from those metals and alloys which are relatively corrosion resistant, possess the requisite structural strengths and can be successfully fabricated.v Particularly useful construction materials are the chromium containing stainless steels, nickel, nickel-alloys, Stellite alloys and the like.

The gas used as the accelerating medium is to be chosen from the low molecular weight gases which exhibitlowv viscosities. Preferably, either high purity Vhydrogen or helium will be used either alone or as a mixture. Advantageously the gas will be of high purity to eliminate therefrom impurities of more` viscous gaseous materials. Hydrogen because of itsready availability and exceed- 'ingly low molecular weight is the most desiredaccelera- Weight accelerating gas in each of the ascending sections of the storage vessel to a successively higher predetermined temperature than the gas in the stage directly below Yrapidly can be separated by a cyclic adsorption process.

Any electrochemical source of hydrogen in close proximity to the launching site also is a ready source of the gas-1 The reserve supply of the gas is stored in long tubes extending outwardlyy from the pressure chambers as shown in FIGURE 1. Alternatively, in certain locations, salt domes and the like formations as shown in FIG- URE 2, canV be utilized to store a suiicient quantity of compressed hydrogen to provide enough energy to propel as many as 100 or more missiles without the necessity of recovering Vany of the hydrogen after each firing.y

The'following example'will serve to further illustrate Vthe instant method of launching utilizing the new and novel system as set forth hereinbefo're. For illustrative Y purposes, an y11 stage `accelerator tube and ten gas pressure vessels can be installed in an excavation shaft about 6400 feet deep. The accelerator tube can be about 8 feet in diameter to accommodate a correspondingly sized rocket and thel gas storage Vessels also can bev about this same size.

The gate vales from'the pressure tanks to the accelerator tube at the various stages each will have an opening of about 3 Yinch width and about 20 feet long.

Y The selection of this particular'length of accelerator tube is arbitrary in that with this particular system steady and rapid acceleration of the rocket to an exit velocity of about 6400 feet per second is readily achieved. This velocity is about the same as that achieved with the chemically fueled first stage presently used in the larger rockets. f

In carrying out the launching, the gate valve 11 in the upper portion of the accelerator tube is closed. Fifty large vacuum pumps, one each aflixed to one of the within about 15 minutes to an absolute pressure of about Y l0 millimeters of mercury. Simultaneously, the removable dome is fastened to the top flange of the accelerator Ytube byevacuation of this section through connection 16.

fAdvantageously, the assembly is suitably dampened to eliminatel mechanical vibrations generated during the evacuation process. After the evacuation is complete,

' the gate-valve 11 is automatically opened prior to loading the missile in thevacuum lock at the base of the accelerator. A rocket of about 110,000 pounds total mass, i.e. about 10,000 pounds payload and about 100,000 pounds weight for the second and thirdstages including both fuel and structure is then inserted, through the vacuum lock, into the bottom of the accelerator tube at stage 0. v i Y The tungsten arc heaters in the various sections of the pressurized gas storage tanks are activated to kheat the hydrogen gas contained therein to a predetermined temperature of about 100 C. at stage 0 and to an increasing temperature for each of the succeeding stages up the tube to a maximum temperature of about 1100 C. at stage l0. This heating is` accomplished within a period of about 5 minutes prior to the rocket launching.

At the` predetermined launching time, the gate-valves n at stage 0 of the 10 hydrogen pressureV chambers are opened simultaneously, i.e. within about 0.01 sec. thereby introducinginto the accelerator high pressure hydrogen at a temperature of about C. This gas exerts a predetermined force of about 1520 pounds per square inch against the rigid nozzle structure of the rocket. As the rocket is raised to stage 1, the l0 gate-valves yat this position are opened whereby hydrogen of an increased temsecond and third stages.

perature and pressure is introduced into the tube thereby accelerating the vrocket to the next stage; As the valves at stagejl are opened Ysimultaneously those at stage ,0 are i closed. 'I'his process isrepeatedstage by stage until the rocket passes stage 10. As the rocket approaches stage V"follows lists the rocket vposition as a function ottime during 1ts passage up the accelerator tube.

Table 1 Accelerator stage t./sec t./sec. HzI" C.

Second stage rocket motor takes over as vehicle exits from launcher 2 000 6, 400

As the rocket leaves the launcher, a quantity of the hydrogen,` gas will be vented to theV atmosphere before the top gate-valve can be closed. However, that portion of gas retained in the accelerator tube after reclosing the valve canbe pumped back to storage until the pressure in the accelerator reaches a value of about 1 atmosphere. As this pressure is reached, the tube is evacuated and the remaining hydrogen vented from the system so as to prevent any possible air contamination of the working gas.

[To uniformly acceleratev the 110,000 pound rocket Within about 2 seconds from zero velocity to about 6400 feet/ second requires power generation of about 3.5 l010 foot pounds per second. This is equivalent to about i 4.74)(107 kilowatts. This supply of energy mechanically is `obtained in the instant launching system by compressing about 400 million cubic feet of hydrogen gas from about 15 p.s.i.g. to about 2000 p.s.i.g. The so-compressed gas is storedin the pressure tanks and about percent of the potential energy contained therein is released within 2 seconds into the evacuated eleven stage linear'accelerator as shown in FIGURE 1.

'I'he total power required for compressing ofthe gas and evacuating the accelerator tube ranges from about 1.88)(105 to about 3.1)(105 horsepower. The heating load required to heat the hydrogen in the pressure vessels to the predetermined temperatures for the various stages is about 2.20)( l06 kilowatts.

In this method of launching during the initial acceleration Vthe nozzle structure of the rocket is subjected to high pressures. Therefore, the nozzle and rocket body must '.be of a rugged structure to withstand the external presisures.- The necessary strength can be incorporated into .the rocket structure by use of conventional ribbing, struts and thev like strengthening members. Additionally, the

internal structure of the rocket itself can be comprised of' tubularmagnesium or other readily oxidizable structural members. These latter members offer the advantage of not only imparting the necessary strength to the structure, but also' are consumed as a fuel during the iiring of the The nozzle exit of the rocket is iitted with a rejectable plug to protect the nozzle during the launching. This plug is pushed from the nozzleby the exhaust gases as the chemical fuel of the second stage is ignited.

' as dictated by the size,and weight of a given rocket to be launched. k The launching'y system alsocan be rmodified. to obtain launching velocities' either higher or lower than shown for the illustrative example presented herein., The

number of stages can be Variedfrom that set forth' and the mechanism of introducing the gas into the accelerator tube can be varied. Furtherthe number of presssure storage chambers for the gas can be changed as desired for agiven launching system. Additionally, it is understood that a suitable camouflage cover can be provided to disguise the location of the launching system. These and other modifications can be made in the instant invention without departing from the spirit or scope thereof for it is understood that I limit myself only as defined in the appended claims.

I claim:

1. An underground apparatus for launching rocket driven vehicles including said vehicle which comprises;

a. multistage, rigid, smooth-bore, evacuable accelerator tube, said tube being positioned vertically underground with its upper end at about ground surface level and having a iiange at its top, said accelerator tube having a gas vent system near the bottom for removal and purging of excess gases from said tube subsequent to a launching of said vehicle,

a vacuum lock attached -to the bottom of said accelerator tube for holding a rocket driven vehicle to be launched whereby said vehicle is introduced into sa'id accelerator tube,

a multiplicity of gas storage vessels surrounding said accelerator tube, each of said gas storage vessels being substantially the same length as said accelerator tube, each of said gas storage vessels divided internally into sections corresponding in length to the stages of said accelerator tube, each of said gas storage vessels containing a compressed, low molecular Weight gas selected from the group consisting of hydrogen, helium and mixtures thereof and each of said sections of said gas storage Vessels fitted with a tungsten arc heat producing device in its upper portion,

an individual conduit leading from each section of each of said gas storage vessels to a corresponding stage of said accelerator tube, each of said conduits positioned ynear said tungsten arc producing device, and

each of said conduits having an automatic-valving mechanism therein,

a iirst columnated `iysource and detector mounted on the wall of said accelerator tubeV at a predetermined position in each stage of said tube, a second detector mounted at a second position in the same stage on the wall of said accelerator tube, said detectors connected to activating mechanisms whereby the valving mechanism of the next successive stage of the accelerator tube is opened and the valving mechanism of a given stage is closed as said vehicle passes therethrough,

a gate valve assembly in the top stage of said accelerrator tube, a multiplicityof connectors in said top stage below said gate valve, said connectors joining said accelerator tube to vacuum turbines,

a removable dome attached to the flange at the top'of said accelerator tube, a connector between said liange and said gate valve whereby the interior of said dome and said accelerator tube above said gate valve is evacuablefand n Y precision-alignment screw aiming assemblies positioned at equal intervals around the top iiange of said `accelerator tube. 2. The apparatus as defined in claim l wherein there are 10 sectionalized highpressure gas chambers located equi-V distantly around the accelerator tube.

`Reizerences Cited the le of this patent .n

UNlTED STATES PATENTS 8 2,872,846 Crozier Feb. 10, 1959 2,953,065 BrownV Sept. 20, 1960 2,981,152 'Miller et al. Apr. 25A, 1961 '3,011,406' Werle etal. Dec. 5, 1961 OTHER REFERENCES.

Rocket J et and Missile Engineering by Constantin Paul Lent, pages 26 and 27, Pen Ink Publishing C0., 1958. 

1. AN UNDERGROUND APPARATUS FOR LAUNCHING ROCKET DRIVEN VEHICLES INCLUDING SAID VEHICLE WHICH COMPRISES; A MULTISTAGE, RIGID, SMOOTH-BORE, EVACUABLE ACCELERATOR TUBE, SAID TUBE BEING POSITIONED VERTICALLY UNDERGROUND WITH ITS UPPER END AT ABOUT GROUND SURFACE LEVEL AND HAVING A FLANGE AT ITS TOP, SAID ACCELERATOR TUBE HAVING A GAS VENT SYSTEM NEAR THE BOTTOM FOR REMOVAL AND PURGING OF EXCESS GASES FROM SAID TUBE SUBSEQUENT TO A LAUNCHING OF SAID VEHICLE. A VACUUM LOCK ATTACHED TO THE BOTTOM OF SAID ACCELERATOR TUBE FOR HOLDING A ROCKET DRIVEN VEHICLE TO BE LAUNCHED WHEREBY SAID VEHICLE IS INTRODUCED INTO SAID ACCELERATOR TUBE, A MULTIPLICITY OF GAS STORAGE VESSELS SURROUNDING SAID ACCELERATOR TUBE, EACH OF SAID GAS STORAGE VESSELS BEING SUBSTANTIALLY THE SAME LENGTH AS SAID ACCELERATOR TUBE, EACH OF SAID GAS STORAGE VESSELS DIVIDED INTERNALLY INTO SECTIONS CORRESPONDING IN LENGTH TO THE STAGES OF SAID ACCELERATOR TUBE, EACH OF SAID GAS STORAGE VESSELS CONTAINING A COMPRESSED, LOW MOLECULAR WEIGHT GAS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN, HELIUM AND MIXTURES THEREOF AND EACH OF SAID SECTIONS OF SAID GAS STORAGE VESSELS FITTED WITH A TUNGSTEN ARC HEAT PRODUCING DEVICE IN ITS UPPER PORTION, 